RESUMO
BACKGROUND: Documentation of structured quality indicators for mycobacteriology laboratories supporting exclusively controlled clinical trials in pulmonary tuberculosis (PTB) is lacking. OBJECTIVE: To document laboratory indicators for a solid (Lowenstein-Jensen medium) culture system in a mycobacteriology laboratory for a period of 4years (2007-2010). METHODS: The sputum samples, collected from PTB suspects/patients enrolled in clinical trials, were subjected to fluorescence microscopy, culture and drug sensitivity testing (DST). Data was retrospectively collected from TB laboratory registers and computed using pre-formulated Microsoft Office Excel. Laboratory indicators were calculated and analyzed. RESULTS: The number of samples processed in a calendar year varied from 6261 to 10,710. Of the samples processed in a calendar year, specimen contamination (4.8-6.9%), culture positives (78.4-85.1%) among smear positives, smear positives (71.8-79.0%) among culture positive samples, smear negatives among culture negative samples (95.2-96.7%), and average time to report DST results (76-97days) varied as shown in parentheses. CONCLUSION: Values of quality indicators in mycobacteriology laboratories supporting exclusively clinical trials of PTB have to be defined and used for meaningful monitoring of laboratories.
RESUMO
To get insight into the sensitivity of fluorescence microscopy for diagnostic and follow-up sputum samples from pulmonary tuberculosis patients in clinical trials, the yield of smear positivity - among culture positive sputum samples - encountered in diagnostic and follow-up samples was retrospectively analyzed from the data available in a mycobacteriology laboratory in India. The sensitivity of fluorescence microscopy for diagnostic and follow-up samples respectively was found to be 94.3% and 60.7%. With these values as guidelines, the performance of fluorescence microscopy in the treatment of multi-drug resistant tuberculosis under DOTS plus program remains to be monitored and studied.
RESUMO
BACKGROUND & OBJECTIVES: Sensitivity of Ziehl-Neelsen (ZN) method is known to be low for liquefied sputum smears. Information on the ZN sensitivity for centrifuged deposit smears is not known. This study was carried out to determine the sensitivity of ZN method for acid fast bacilli (AFB) in centrifuged deposit smears and liquefied sputum smears made from sputum samples transported in cetyl-pyridinium chloride (CPC) solution. METHODS: Liquefied sputum smears and the corresponding centrifuged deposit smears from each of the 607 consecutive sputum samples collected from tuberculosis patients admitted to receive treatment transported in CPC were read by the same readers and their results compared with culture results. RESULTS: A significantly (P<0.001) higher proportion of samples were positive in centrifuged deposit smears (40%) compared to liquefied sputum smears (30%). The results of 341 culture-positive specimens revealed that the sensitivity of ZN method was 47 per cent using liquefied sputum smears and 63 per cent using centrifuged deposit smears (P<0.001). INTERPRETATION & CONCLUSION: Our study demonstrated that the sensitivity of ZN method for AFB in centrifuged deposit smears and liquefied sputum smears was reduced if sputum samples are transported in CPC solution.